A backpack of the type intended for use in back country travel and exploration should enable a wearer thereof to carry a sizable load containing needed clothes, food, supplies, etc., on his or her back in comfort for prolonged periods of time. It is also desirable that the backpack frame be strong and fabricated from light weight materials and be designed with backpack loading weight distribution considerations in mind. To this end, backpacks having external H-type frame configurations constructed of sturdy light weight materials, such as tubular aluminum members, have proved very popular.
Although these types of backpacks are comfortable and pleasant to wear for prolonged periods, it is still necessary to take the backpack off from time to time so that the user may sit down and rest his or her legs. For such situations, it is desirable to provide an above ground chair having a back rest so that the backpacker can comfortably sit in a reclined position without soiling his or her trousers.
The prior art is replete with backpacks which describe the use of a multi-part backpack frame wherein a portion of the frame articulates to permit conversion of the backpack frame into a camp chair. U.S. Pat. Nos. 4,300,707 (Kjaer) and 4,720,029 (Varanakis) are examples of one type of backpack/chair conversion wherein a first generally upright rectangular backpack frame member has pivotally connected thereto the terminal free ends of a second U-shaped frame member which, when pivoted through a rearward arcuate direction (i.e., through an arcuate direction away from the wearer's back) forms the seat portion of a chair. In the chair use position, the pack must be removed from the backpack frame before the user may sit down into the converted chair.
U.S. Pat. Nos. 4,450,990 (Bolstad) and 4,487,345 (Pierce et al.) are examples of a second type of convertible backpack chair wherein the loaded pack is left on the backpack frame during the chair conversion process. The Bolstad patent teaches to covert his backpack frame into a chair by partial disassembly, reorientation and reassembly of some of the component parts of the backpack frame. This approach adds undesirable complexity and weight to the backpack frame.
Pierce is directed to a chair convertible backpack frame which includes a plurality of pivotally connected frame subassemblies which articulate outwardly in an accordion-type fashion to form a low lying parallelogram chair support structure complete with arm rest. The parallelogram support structure, while sturdy, adds a significant amount of additional weight to the backpack frame.
U.S. Pat. No. 4,795,068 issued to Blean discloses a backpack chair wherein a single U-shaped frame member is pivotally attached to the upright side members of a backpack frame. The U-shaped frame member cooperates with the adjustable shoulder straps of the backpack frame to form a seat when pivoted to a position orthogonal to the vertical axis of the backpack frame. The bottom portion of the vertical backpack frame forms the front leg support for the chair while support for the rear leg is formed by leaning the backpack against the nearest firm vertical surface, such as a tree or rock. Although implementation of the additional U-shaped frame member with an existing backpack frame is simple and adds minimal extra weight, its utility as a convertible backpack chair is limited to specific site locations, i.e., limited only to those sites having a suitable vertical support surface close by.
Accordingly, there is a definite need in the art for a self supported convertible backpack chair which is of light weight construction and is easy to implement.